It was in the heart of winter of 2013, just after solstice. Guillemette and I took up to Nordskot in Norway, above the Arctic Circle, to visit our supplier Roderick Sloan for the first time.

L to R: Guillemette; Pawel, Roddie's assistant; and Roddie.

The sun would not rise, per se—more approach the horizon asymptotically from below, hover for a while under the glow, and descend again. There was, for a few hours if there was also luck, some light, and none of it direct.

Sometimes we used our brief day out on the water, checking sites, scouting new ones. Others we spent walking the wet heath, fishing with the kids at the fjord's inlet, and stumbling upon things surely known to others but not, at that time, to us.

The birch bud was the primary one.

Birch trees surround Roddie's property. As we walked through the brush we would absent-mindedly pick a twig, a leaf, or in this case, a bud so aromatic the resinous smear stayed on our fingers hours after crushing it.

This small discovery prompted a few sole-purpose excursions to pick as many as we could before our bare hands would refuse from the cold. The trees were mostly short and dense, which made them easy to pick from, and everywhere, which made it easy to not over-harvest from any one.

After picking, the best and easiest way we had to preserve their potency was to pound them with salt. This seemed to retain their powerful aroma and yielded a fine salt with a satisfying moist feel.

We returned to the lab in January excited with our find. It proved versatile.

Then, in April/May, Guillemette went up to Jämtland in Sweden to spend some weeks working with Peter Blombergsson—perhaps more popularly known as 'the Duck Man', through his relationship with Restaurant Fäviken—and his ducks. There, the birch buds had still not yet begun to open, and she managed to pick quite a good amount and this time put them into tincture.

We have noticed, while harvesting buds at different times and from a few different places, that the buds seem to be at their best—most aromatic and least bitter—deepest in winter and often further north, where and when the weather is coldest, long before any sign of spring begins the transformations that lead them to unfurl into new leaves.

Michael harvesting birch buds in Småland, Sweden, January 2015.

After experimenting casually with the salt and tincture, we settled on a way to incorporate the sweet, heady aroma into a dish. We presented it with dessert at The Science of Taste Symposium at the Royal Danish Academy of Arts and Letters in August 2014: lemon verbena koldskål with freeze-dried berries, lemon thyme sugar, kammerjunkere, and the birch bud tincture vaporised over the tables as it was served.

This little gem continues to hang around the lab finding its way into different things, and it's about time to share it.

For more on birch, check out some of our other work with the sap, bark, and the chaga fungus.